1. Solar System Organization Chapters 3 & 4

2. Forming the Solar System Accretion- the process of building something up gradually by the gathering together of small pieces Explain how this would build a star? The solar system?

3. Gravity Newton’s Law of Gravity- stated that every object in the universe attracts every other object The strength of the force of gravity between the two objects depends on two factors: the masses of the objects and the distance between them.

4. What Determines Gravity? Earth revolves around the sun in a nearly circular orbit Orbit- path of an object as it revolves around another object in space What keeps the Earth and the moon from flying off into space?

5. Inertia Inertia- the tendency of an object to resist change in motion You feel the effects of inertia everyday when riding in a car and it brakes suddenly. The car stops, but you fly forward (that’s why they invented the seatbelt!) The more mass an object has, the more inertia The more mass and inertia the harder it is for the object to stop (give an example)

6. Inertia Isaac Newton created a law about inertia Newton’s First Law of Motion- that an object at rest will stay at rest and an object in motion will stay in motion with a constant speed and direction unless acted upon by a force

7. Models of the Solar System 4.6 There are two models of the solar system

8. What is the Geocentric Model? Geocentric- Earth is at the center of the revolving planets and stars Ptolemy took the geocentric model a little further by saying that moved in circles carried along by larger circles This helped to explain what we see in the sky

9. Geocentric Model

10. How did the Heliocentric model develop? Heliocentric model- sun centered All planets revolve around the sun Aristarchus first developed this idea Many scientists further developed the heliocentric idea

11. Heliocentric Model

12. Copernicus was able to work out the arrangement of the known planets and how they moved around the sun Brahe and Kepler furthered the idea after years of detailed calculations, Kepler found that the obit of each planet is an ellipse ( oval shape) Galileo evidence gradually convinced other that the heliocentric model was correct